Whether various fields or methods that are said to be scientific, expert, or specialized knowledge are sufficiently reliable to satisfy the requirements of Federal Rule of Evidence 702 or comparable State rules for the admissibility of expert evidence

Fed. R. Evid. 609(a)(1) ("(a) General rule. For the purpose of attacking the character for truthfulness of a witness, (1) ... evidence that an accused has been convicted of such a crime [crime punishable by death or imprisonment in excess of one year under the law under which the witness was convicted] shall be admitted if the court...If a conviction for a crime other than one involving dishonesty or false statement is offered to impeach a criminal defendant, the conviction is admissible only if the proponent shows that the probative value of the criminal conviction on the issue of the truthfulness of the witness -- the criminal defendant -- outweighs the risk of prejudice to the criminal defendant.

Mahone v. Lehman, 347 F.3d 1170, 1173-1174 (9th Cir. 2003) (holding, in plaintiff inmate's civil rights action against defendant prison officials, that the psychiatrist's opinion was inadmissible hearsay because the....Hearsay evidence is inadmissible.

United States v. Bruguier, 161 F.3d 1145, 1148-1150 (8th Cir. 1998) (upholding trial court's ruling which allowed the government to cross-examine the accused's opinion character evidence witnesses on their knowledge about specific incidents in order to explore the bases for holding such opinions).Although a character witness who testifies to the reputation of another person or gives an opinion of the character of another person cannot testify to specific instances of that person's conduct to bolster the character witness's testimony, an opposing party may question the character witness about specific instances of the person's conduct to show that the character witness' testimony about the character of the person was not well-founded.